Database Accession: DI2100007
Name: RbcX-IIa from Chlamydomonas reinhardtii in complex with RbcL C-terminal tail
PDB ID: 5bs2
Experimental method: X-ray (1.97 Å)
Source organism: Chlamydomonas reinhardtii
Proof of disorder:
Primary publication of the structure:
Bracher A, Hauser T, Liu C, Hartl FU, Hayer-Hartl M
Structural Analysis of the Rubisco-Assembly Chaperone RbcX-II from Chlamydomonas reinhardtii.
(2015) PLoS ONE 10: e0135448
PMID: 26305355
Abstract:
The most prevalent form of the Rubisco enzyme is a complex of eight catalytic large subunits (RbcL) and eight regulatory small subunits (RbcS). Rubisco biogenesis depends on the assistance by specific molecular chaperones. The assembly chaperone RbcX stabilizes the RbcL subunits after folding by chaperonin and mediates their assembly to the RbcL8 core complex, from which RbcX is displaced by RbcS to form active holoenzyme. Two isoforms of RbcX are found in eukaryotes, RbcX-I, which is more closely related to cyanobacterial RbcX, and the more distant RbcX-II. The green algae Chlamydomonas reinhardtii contains only RbcX-II isoforms, CrRbcX-IIa and CrRbcX-IIb. Here we solved the crystal structure of CrRbcX-IIa and show that it forms an arc-shaped dimer with a central hydrophobic cleft for binding the C-terminal sequence of RbcL. Like other RbcX proteins, CrRbcX-IIa supports the assembly of cyanobacterial Rubisco in vitro, albeit with reduced activity relative to cyanobacterial RbcX-I. Structural analysis of a fusion protein of CrRbcX-IIa and the C-terminal peptide of RbcL suggests that the peptide binding mode of RbcX-II may differ from that of cyanobacterial RbcX. RbcX homologs appear to have adapted to their cognate Rubisco clients as a result of co-evolution.
Annotations from the GeneOntology database. Only terms that fit at least two of the interacting proteins are shown.Molecular function: not assigned
Biological process: not assigned
Cellular component: not assigned
Structural annotations of the participating protein chains.Entry contents: 3 distinct polypeptide molecules
Chains: R, A, B
Notes: No modifications of the original PDB file.
Name: Ribulose bisphosphate carboxylase large chain
Source organism: Chlamydomonas reinhardtii
Length: 6 residues
Sequence:Sequence according to PDB SEQRESWKEIKF
UniProtKB AC: P00877 (positions: 462-467) Coverage: 1.3%
UniRef90 AC: UniRef90_P00877 (positions: 462-467)
Name: Predicted protein (Fragment)
Source organism: Chlamydomonas reinhardtii
Length: 132 residues
Sequence:Sequence according to PDB SEQRESWKEIKFEFDTIDPADSFSGASPERKAAVALRSLFTFVAARVVLEQLQGPGGPETTYNQQAYLDLMDFLGTPMKGDGGDEWMAAVMRKNHALALRLMEVREAYLDEFEWGKTMEMASRETREANTRLMRAAAM
UniProtKB AC: A8HQH2 (positions: 25-156) Coverage: 65.7%
UniRef90 AC: UniRef90_A8HQH2 (positions: 37-156)
Name: Predicted protein (Fragment)
Source organism: Chlamydomonas reinhardtii
Length: 132 residues
Sequence:Sequence according to PDB SEQRESWKEIKFEFDTIDPADSFSGASPERKAAVALRSLFTFVAARVVLEQLQGPGGPETTYNQQAYLDLMDFLGTPMKGDGGDEWMAAVMRKNHALALRLMEVREAYLDEFEWGKTMEMASRETREANTRLMRAAAM
UniProtKB AC: A8HQH2 (positions: 25-156) Coverage: 65.7%
UniRef90 AC: UniRef90_A8HQH2 (positions: 37-156)
Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding. Chain R:
The interacting region of the protein has been shown to be highly flexible corresponding to missing coordinates in X-ray structure (PDB ID: 2v69).
Chain A:
The RcbX domain involved in the interaction is known to adopt a stable structure in isolation in dimeric form (see Pfam domain PF02341). A solved structure of the domain dimer without bound ligands is represented by PDB ID 5bs1.
Chain B:
The RcbX domain involved in the interaction is known to adopt a stable structure in isolation in dimeric form (see Pfam domain PF02341). A solved structure of the domain dimer without bound ligands is represented by PDB ID 5bs1.
Structures from the PDB that contain the same number of proteins, and the proteins from the two structures show a sufficient degree of pairwise similarity, i.e. they belong to the same UniRef90 cluster (the full proteins exhibit at least 90% sequence identity) and convey roughly the same region to their respective interactions (the two regions from the two proteins share a minimum of 70% overlap). The structure can be rotated by left click and hold anywhere on the structure. Representation options can be edited by right clicking on the structure window.
